PHOTOS: New harmful algae bloom advisories at 5 Wyoming waters, including Pathfinder - Casper, WY Oil City News
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PHOTOS: New harmful algae bloom advisories at 5 Wyoming waters, including Pathfinder

Woodruff Narrows (Wyoming DEQ)

CASPER, Wyo. — The Wyoming Department of Environmental Quality listed new recreational use advisories for five reservoirs or bodies of water in the state on Thursday, Aug. 13. The advisories are due to the presence of harmful algae blooms.

Those bodies of water include:

  • Pathfinder Reservoir
  • Lower North Crow Reservoir
  • Big Sandy Reservoir
  • Eden Reservoir
  • Woodruff Narrows Reservoir

There are now a total of 11 bodies of water in Wyoming where harmful algae bloom advisories are in effect. In addition to the five announced Thursday, advisories are in effect at:

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  • Boysen Reservoir
  • Ocean Lake
  • Saratoga Lake
  • Wheatland Reservoir #3
  • Leazenby Lake
  • Seminoe Reservoir

The Wyoming DEQ is also investigating possible harmful algae blooms at:

  • Keyhole Reservoir
  • Brooks Lake
  • Jackson Lake
  • Gillette Fishing Lake

The Wyoming DEQ offers details regarding the blooms at each body of water on their “Harmful Cyanobacterial Bloom (HCB) Advisories in Wyoming Waters” webpage. 

“HCBs are also referred to as harmful algal blooms (HABs) since cyanobacteria are commonly known as blue-green algae,” the Wyoming DEQ explains. “The Department of Health issues advisories to inform the public that there may be health risks for people and animals in areas where HCBs occur.”

“Lakes and reservoirs under a recreational use advisory are not closed since HCBs may only be present in certain areas of the waterbody and conditions can change frequently. The advisory will remain in place until the bloom has fully dissipated and cyanotoxin concentrations are below recreational use thresholds identified in Wyoming’s HCB Action Plan, or until the primary recreation season ends on September 30th, whichever comes first.”

People who encounter possible harmful blooms are provided the following recommendations from the Wyoming DEQ and Wyoming Livestock Board:

  • Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scums.
  • Do not ingest water from the bloom. Boiling, filtration and/or other treatments will not remove toxins.
  • Rinse fish with clean water and eat only the fillet portion.
  • Avoid water spray from the bloom.
  • Do not allow pets or livestock to drink water near the bloom, eat bloom material, or lick fur after contact.
  • If people, pets, or livestock come into contact with a bloom, rinse off with clean water as soon as possible and contact a doctor or veterinarian.

Questions about health effects and recreational use advisories can be directed to Dr. Karl Musgrave, State Environmental Health Epidemiologist / State Public Health Veterinarian, Wyoming Department of Health, at or (307) 777-5825.

Questions regarding cyanobacteria sampling can be directed to Michael Thomas, Natural Resource Analyst, Wyoming Department of Environmental Quality, at or (307) 777-2073, or Lindsay Patterson, Surface Water Quality Standards Coordinator, Wyoming Department of Environmental Quality, at or (307) 777-7079.

Wyoming DEQ
Pathfinder Reservoir (Wyoming DEQ)
Eden Reservoir (Wyoming DEQ)
Big Sandy Reservoir (Wyoming DEQ)
Lower North Crow Reservoir (Wyoming DEQ)
Saratoga Lake (Wyoming DEQ)
Leazenby Lake (Hundred Springs Reservoir) (Wyoming DEQ)
Wheatland Reservoir #3 (Wyoming DEQ)
Ocean Lake (Wyoming DEQ)
Seminoe Reservoir (Wyoming DEQ)
Boysen Reservoir (Wyoming DEQ)